[Septic arthritis caused by S. pneumoniae. Report of 2 cases with unusual location].

Arthritis by S. pneumoniae, although no frequent, is a well-known disease in patients with underlying diseases and in which they complaint previous articular disease. In the present article 2 cases of location in shoulder and sacroiliac joints are described respectively in a woman with multiple myeloma and an esplenectomizaded man, associations nondescribed previously in literature. The importance of its suspicion in patients with factors of risk for sepsis by S. pneumoniae is emphasized.